international, a major u.s. contractor in the war zone, working to help mentor and train afghan police forces. this is the latest of the so-called insider attacked that have plagued the forces over the past year. many active duty forces killed, contract contractors. 50 deaths this year. they haven't been able to get a handle on it. hala? >> and these attacks have been increasing. what is the reason behind the increase in attacks. >> this is -- they have increased throughout the year, but over the course of the year, ebbed and flowed, thankfully where there hasn't been one in several weeks. the military, the intelligence effort in the military has been to try to figure out the answer to that very question. what is going on. why is this happening? some of them are said to be taliban infiltrations. but there is a sense we're told that many of them are due, how to describe it, to cultural differences. afghans who feel a grudge, perhaps, to how they are treated by forces and western personnel, crossed signals, conver